Field of the Invention
The present invention relates to an imprint method, an imprint apparatus, and a method of manufacturing an article.
Description of the Related Art
An imprint technique that transfers a pattern formed on a mold onto a substrate is attracting attention as one of lithography techniques. In an imprint apparatus using such imprint technique, a mold including a pattern surface on which a fine uneven pattern is formed is brought into contact with an imprint material (resin) supplied onto a substrate. When the mold and the resin are brought into contact with each other, if air bubbles remain in a concave portion of the pattern, loss of the pattern transferred onto the substrate may occur. To solve this problem, an imprint apparatus described in Japanese Patent Laid-Open No. 2009-536591 suppresses air bubbles remaining in a concave portion of a pattern by deforming a pattern surface into a convex shape to bend toward a substrate, and bringing a mold into contact with a resin.
On the other hand, an imprint apparatus is also required to accurately transfer the pattern of a mold to a shot region formed on a substrate. To achieve this, Japanese Patent No. 4185941 proposes an imprint apparatus using a die-by-die alignment method as an alignment method when transferring the pattern of a mold to a shot region. The die-by-die alignment method is an alignment method of optically detecting a mark formed in each shot region on a substrate and a mark formed on a mold, thereby correcting a relative positional shift between the substrate and the mold.
When the entire pattern formed on the mold comes into contact with the resin on the substrate, deformation of the pattern surface (convex shape) becomes small. If the mold and the substrate are aligned in this state, a shearing stress occurs, thereby making it difficult to change the relative positions of the mold and substrate. It takes considerable time to perform alignment. Therefore, before the entire pattern of the mold comes into contact with the resin, that is, while the pattern surface is deformed, it is desirable to align the mold and the substrate. However, while the pattern surface of the mold is deformed, the positions of marks formed on the mold change, as compared with those before deformation. It is thus difficult to accurately perform alignment.